Electrocatalytic　depolymerization　of　lignin　into　value-added　chemicals　offers　a　promising　technique　to　make　biorefining　sustainable.　Herein,　we　report　a　robust　trimetallic　PdNiBi　electrocatalyst　for　reductive　C-O　bond　cleavage　of　different　lignin　model　dimers　and　oxidized　lignin　under　mild　conditions.　The　reduction　reaction　proceeds　with　complete　substrate　conversion　and　excellent　yields　toward　monomers　of　phenols　(80%–99%)　and　acetophenones　(75%–96%)　in　the　presence　of　an　ionic　liquid　electrolyte　with　operational　stability.　Systematic　experimental　investigations　together　with　density　functional　theory　(DFT)　calculations　reveal　that　the　outstanding　performance　of　the　catalyst　results　from　the　synergistic　effect　of　the　metal　elements,　which　facilitates　the　easier　formation　of　a　key　Cα　radical　intermediate　and　the　facile　desorption　of　the　as-formed　products　at　the　electrode.　The　results　open　up　new　opportunities　for　lignin　valorization　through　the　green　electrocatalytic　approach.　©　Tsinghua　University　Press　2023.